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Hypothetically speaking, if you generate a 10 kHz square wave of around one Volt and inject it into the varactor-diode circuit in a PLL radio's VCO you'll get FM sidebands.

The FM sideband of a carrier is... a carrier. And it will be separated from the original carrier by the modulation frequency. And a 10 kHz FM modulation will have sidebands every 10 kHz. How many of them depends on the modulation level. The FM-modulation level, that is.

Crank up the level of that square wave, more sidebands. There is a phenomenon called the "Bessel null" that will cause some of the sidebands to be weaker than others. This depends entirely on the FM-modulation level of the square wave.

Those FM sidebands will be clean-sounding "clones" of the AM signal on the original channel frequency.

If it's done right.

Hypothetically, anyway.

73

<blockquote data-quote="nomadradio" data-source="post: 766913" data-attributes="member: 22">Hypothetically speaking, if you generate a 10 kHz square wave of around one Volt and inject it into the varactor-diode circuit in a PLL radio&#039;s VCO you&#039;ll get FM sidebands.The FM sideband of a carrier is... a carrier. And it will be separated from the original carrier by the modulation frequency. And a 10 kHz FM modulation will have sidebands every 10 kHz. How many of them depends on the modulation level. The FM-modulation level, that is.Crank up the level of that square wave, more sidebands. There is a phenomenon called the &quot;Bessel null&quot; that will cause some of the sidebands to be weaker than others. This depends entirely on the FM-modulation level of the square wave.Those FM sidebands will be clean-sounding &quot;clones&quot; of the AM signal on the original channel frequency.If it&#039;s done right.Hypothetically, anyway.73</blockquote>

[QUOTE="nomadradio, post: 766913, member: 22"] Hypothetically speaking, if you generate a 10 kHz square wave of around one Volt and inject it into the varactor-diode circuit in a PLL radio's VCO you'll get FM sidebands. The FM sideband of a carrier is... a carrier. And it will be separated from the original carrier by the modulation frequency. And a 10 kHz FM modulation will have sidebands every 10 kHz. How many of them depends on the modulation level. The FM-modulation level, that is. Crank up the level of that square wave, more sidebands. There is a phenomenon called the "Bessel null" that will cause some of the sidebands to be weaker than others. This depends entirely on the FM-modulation level of the square wave. Those FM sidebands will be clean-sounding "clones" of the AM signal on the original channel frequency. If it's done right. Hypothetically, anyway. 73 [/QUOTE]

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